Package Included: 4 standard countersinks and 4 4-flute chamfer cutters. The chamfer cutters make tapered plugs to fill countersunk holes. Diameter sizes include 6mm / 10mm / 13mm / 16mm (1/4 , 3/8 , 1/2 , 8/5) Shank Diameter: 9.3mm. 8-piece cutter set: Makes perfect plugs for drilled holes. Easy and safe to use and store. Material: Carbon steel, titanium coated, durable and high precision. Reduce drilling resistance, reduce heat, bit more durable. lucky meet